ReveraGen BioPharma is a clinical stage drug development company that is developing VBP15, a novel dissociative steroidal class drug. The initial indication for development is Duchenne muscular dystrophy, where VBP15 holds promise for retaining or increasing efficacy of glucocorticoids, while reducing side effects (bone fragilit, stunting of growth). VBP15 is currently in Phase I clinical trials in adult volunteers. This proposed Phase II SBIR research is to carry out a Phase IIa clinical trial in Duchenne muscular dystrophy boys, steroid nave, ages 4-7 yrs. Aim 1 is to test four dose levels of VBP15 in a multiple ascending dose (MAD) trial design, with two weeks on drug. Patients completing the Phase IIa clinical trial will be offered enrollment into a six month extension study. The goal is t test pediatric pharmacokinetics, tolerability and safety in the Phase IIa clinical trial, and assessments of efficacy (time to stand velocity) and safety (change in body mass index) in the six month extension study to aid dose selection in the future Phase IIb registration trial. Aim 2 i to develop a pharmacodynamics biomarker panel that can assess safety and efficacy markers in acute time frames from peripheral blood. We have completed a natural history of DMD serum biomarkers using both SomaScan and proteomics discovery methods, and present preliminary data on glucocorticoid- associated efficacy and safety biomarkers. The Phase II SBIR research will compare VBP15 biomarkers to glucocorticoid biomarkers as a means of assessing comparative safety and potential efficacy.